1. Field of the Invention
The present invention relates to an image-displaying device and a pixel control method therefor, and more particularly, to an image-displaying device and a pixel control method therefor capable of adaptively enhancing brightness and contrast.
2. Description of the Related Art
Information provided to users through image-displaying devices includes not only simple text information but also diverse multimedia information.
In particular, since moving pictures out of the multimedia information of diverse types underlies next-generation Video on Demand (VOD) services or interactive services, studies on related standard specification are actively ongoing.
The developments of digital electronics technologies have digitized conventional analog data, which has brought about technologies for processing diverse digital image materials to efficiently handle the vast digitized data.
Firstly, since all analog devices introduce noise into original signals upon carrying out certain functions thereon, analog signal recording results in image degradation during processing the original signal.
Secondly, digitizing a signal enables computers to be used to process the digitized signal. That is, it becomes possible to process image information compression or the like since the computers process image signals.
Digital image-processing technologies are technologies related to how to display analog results recorded on media on the computers. The possibility of digital images was turned into reality by the digital video interactive (DVI) mode which the RCA research staff had proposed since late 1980s.
The DVI mode can carry out functions difficult for general processors to process in real time by using a special processor carrying out micro-programmable commands suitable for image processing.
Further, the two Experts groups, the joint photographic experts group (JPEG) and the moving pictures experts group (MPEG), established since 1989 defined the standard coding specification having much better functions than the DVI but having difficulties in implementation in software, and such a coding specification is supposed to play an important role in future digital image developments since most manufacturers have supported the specification.
In particular, the MPEG standard is being improved in specification to new versions such as MPEG2 and MPEG3 for image-processing on personal computers as well as for digitization for high-definition system such as high definition television (HDTV).
Further, technologies have been introduced since 1991 for processing images based on the processing capacity of the main processor without extra software purchases, and the QuickTime of Apple, Video for Windows of Microsoft, and Indeo of Intel typically represent such technologies at present. Such image-processing technologies are specifically spotlighted for personal computers thanks to high-speed main processors.
Standardization tasks are accompanied with the introduction to diverse digital image-processing technologies. The digital image-processing technologies are not limited to video-conferencing systems, digital broadcast codec systems, and video telephone technologies, but widely compatible and shared with computer industries, communication industries, and so on.
For example, digital image compression technologies for information storage on optical disc or digital storage media such as CD-ROM are realized by base technologies nearly similar to compression technologies for video conference and the like. Current MPEG standardization is being carried out by ISO-IEC, JTC1, SC1, and WGI11, and the standardization tasks are still progressing since Experts group establishment in 1990s.
As stated above, diverse approaches are being studied for preventing image degradation since the problem of the image degradation is not solved despite advancement of the above-mentioned digital image-processing technologies.
For example, a non-linear incremental function histogram using a luminance signal has been proposed. However, the histogram using a luminance signal has difficulties in that the same is highly likely to cause a flickering phenomenon of estimated and enhanced light source upon application to moving pictures and to cause color distortion. Moreover, it needs an additional color gamut-mapping algorithm.
Further, diverse approaches have been proposed for improving image quality while preventing image degradation, but the approaches have problems in that the approaches can not produce the maximum performance for image enhancement due to lack of consideration of display characteristics of image-displaying devices. The approaches also and have difficulties in maintaining color tones upon general brightness enhancement.